This invention relates generally to sewing machines for sewing quilts, comforters and analogous articles and, more particularly, is directed to a sewing machine having a rotatable and axially movable cylindrically-shaped frame for holding the fabric.
Because of the large size of quilts, comforters and the like, it is difficult to sew patterns thereon. Further, apparatus for sewing the same must occupy a substantial amount of space because of the large size of quilts and comforters, thereby rendering such apparatus inefficient and space consuming.
In order to overcome some of the disadvantages of conventional apparatus, a sewing machine for sewing quilts, comforters and the like has been designed with a substantially cylindrical frame which is rotatable and axially movable on a base and which can expand or contract its lengthwise dimension. Examples of such sewing machines are found in U.S. Pat. Nos. 351,468; 447,794; 448,253; 456,726; 467,138; 1,937,491; 1,946,868; and 2,377,951.
For example, U.S. Pat. No. 1,937,491 generally discloses a rotatable quilting machine having a substantially cylindrical frame axially movable along a base by pulleys which ride upon a central sleeve of the base and by pulleys which cooperate with an upper T-rail of the base.
The frame is manually moved along the base by the operator.
The length of the frame is also manually adjustable by adjustable collars, and the frame is rotatably mounted upon the aforementioned central sleeve and manually rotated by raising or lowering of a bar by the operator.
U.S. Pat. No. 1,946,868 discloses a similar arrangement. However, a first rod extends from one end and includes internal screw threads and a second rod extends from the opposite end and is screw-threadedly received within the first rod. A crank handle rotates one of the rods to move the outer rings of the cylindrical frame closer together or further apart.
U.S. Pat. No. 2,377,951 expands on the previous Patent by providing a plurality of such screw-threaded telescoping members In addition, drive sprockets are provided at the ends of the screw-threaded members at each end of the frame, and a chain passes over the drive sprockets and various idler sprockets. By means of a wrench which can be placed on a non-circular portion of one of the screw-threaded shafts for rotating the same, all of the screw-threaded shafts at the same end of the frame are rotated by means of the chain drive.
Various other ones of the Patents, such as U.S. Pat. No. 467,138 discloses a rotatable drive mechanism in which the outer rings are provided with gear teeth. Through suitable gearing and a manual crank wheel, the frame can be rotated about a central shaft. See also U.S. Pat. No. 448,253.
As to the axial movement of the frame, U.S. Pat. No. 456,726 discloses the use of two cams which coact with projections to provide side-to-side movement of the carriage in a specific pattern
With all of the above patents, however, the arrangements that are provided for rotating and axially moving the frame are relatively complicated and consume unnecessary space. In addition, there are no automatic means, such as motor means or the like, for controlling rotation, axial movement and elongation of the frame.
In the above discussed patents, the fabric of the quilt or comforter is secured at opposite ends about the substantially cylindrical frame by means of clamping fingers or the like which are manually set. See, for example, U.S. Pat. No. 1,937,491. However, the securement of the fabric to the frame is time consuming and tedious, and therefore inefficient.